Desloratadine is long-acting tricyclic second generation (non-sedating) antihistamine. It is the active metabolite of loratadine and produces the same pharmacologic effect; both antagonist at peripheral histamine (H1) receptors. Histamine is a substance that causes allergic symptoms. When histamine (H1) receptors are blocked, histamine cannot have its effect, and this leads to a decrease in the symptoms of allergy.

As with other second-generation antihistamines, the low incidence of sedation can be attributed to reduced penetration into the CNS

Somnolence has been reported very rarely in patients taking Desloratadine. Caution should be exercised when driving a car or operating potentially dangerous machinery.

Rare cases of hypersensitivity reactions (such as rash, pruritus, urticaria, edema, dyspnea, and anaphylaxis) have been reported. In such cases, stop the drug at once and consider alternative treatments.

Desloratadine passes into breast milk; therefore, a decision should be made whether to discontinue nursing or to discontinue desloratadine, taking into account the benefit of the drug to the nursing mother and the possible risk to the child.